In the first quarter of 2010, devices running Google's Android operating system eclipsed U.S. sales of Apple's iPhone for the first time ever. According to research firm NPD Group, Android sales accounted for 28 percent of the smartphone market, compared with 21 percent for the iPhone. (Blackberry devices still hold the top spot at 36 percent.) In addition to the wide variety of Android phones available, many commentators credit Verizon's buy-one-get-one-free phone promotions with Android's jump in sales. Is this shift in dominance merely a blip on the market radar, or a sign that the iPhone is past its prime? (Watch a report about the Droid's superior sales)